Problem: A bag contains $11$ red jelly beans, $9$ green jelly beans, and $7$ blue jelly beans. If a jelly bean is randomly chosen, what is the probability that it is not green?
Solution: There are $11 + 9 + 7 = 27$ jelly beans in the bag. There are $9$ green jelly beans. That means $27 - 9 = 18$ are not green. The probability is $ \frac{18}{27} = \dfrac{2}{3}$.